Open array radar on 40 footers

[BigAl.NZ]

Does anyone have pictures of installation of an Open Array (3 foot) radar on a 40 footer?

I am looking at it as an option. Our dome was on front of mast, but this wont work for open array. I think on a pole on transom might be ok.

Draw back will be higher power, but the picture is far better.

[Shrew]

IMHO an open array has greater benefit with returning signals at distances, rather than enhanced clarity at short distances. A bigger blob out at 3 miles.

That distance really requires height. You're not going to get the height to benefit from the extra distance an open array mounted on a pole. Then there is the issue with needing a cage to prevent entanglements. The vessel would need to be huge. Space will be an issue on a 40 foot boat.

Just one guys opinion.

[BigAl.NZ]

Originally Posted by Shrew

IMHO an open array has greater benefit with returning signals at distances, rather than enhanced clarity at short distances. A bigger blob out at 3 miles.

That distance really requires height. You're not going to get the height to benefit from the extra distance an open array mounted on a pole. Then there is the issue with needing a cage to prevent entanglements. The vessel would need to be huge. Space will be an issue on a 40 foot boat.

Just one guys opinion.

I am not sure why you think you wont get clarity at short distances? For example the Raymarine Quantum has a beam width of about 5 degrees (closed array) - the Cyclclone has a beam width of about 1.8 degrees (Open array).

That is one of the main factors for target separation at any distance and affects "resolution" of the retuns.

[wayne.b]

Originally Posted by Shrew

IMHO an open array has greater benefit with returning signals at distances, rather than enhanced clarity at short distances. A bigger blob out at 3 miles.

That distance really requires height. You're not going to get the height to benefit from the extra distance an open array mounted on a pole. Then there is the issue with needing a cage to prevent entanglements. The vessel would need to be huge. Space will be an issue on a 40 foot boat.

Just one guys opinion.

===
An open array gives better target resolution regardless of height. Resolution is important for making sense of closely spaced targets or an irregular coast line.

An alternative to a pole is an aluminum tube radar arch which can also double as a dinghy davit.

[Shrew]

Originally Posted by BigAl.NZ

I am not sure why you think you wont get clarity at short distances?

I could have clarified my point better. I didn't say you wouldn't get better clarity. What I was trying to say is with an Open Array you get both greater distances and greater clarity at shorter distances. My commentary is on how beneficial clarity is at short distances. Hence my "Bigger Blob' comment.

At 10 feet above sea-level, the horizon is only 3.696 nautical miles. You won't really get the distance benefit from an open array.

This brings me back to how beneficial is the additional clarity at shorter distances?

How beneficial is the clarity at shorter distances as compared to what it would take to install it?

Are we going to hit something or aren't we? Are we on a collision course or aren't we? Whether that is one object or two a mile out just isn't a concern to me, and we travel a lot at night and in the fog.

[dougweibel]

Shrew,

I wouldn't go for an open array on a 40 footer either, but your answer is a bit incorrect. Sure the horizon is only about 3.7 nm away from a 10' high vantage, but you aren't looking for targets at the water level. The radar will see the side of the ship that sticks up way above the water level at much greater distances. Yes, you cannot see a center console much further out, but the center console is much less a threat than a ship.

Distance eyeballs (or radar) can see something is dependent both on the height of the eyeball and the height of the thing being looked upon.

I expect you know this but it is worth mentioning for others.

[BigAl.NZ]

Originally Posted by dougweibel

Shrew,

I wouldn't go for an open array on a 40 footer either, but your answer is a bit incorrect. Sure the horizon is only about 3.7 nm away from a 10' high vantage, but you aren't looking for targets at the water level. The radar will see the side of the ship that sticks up way above the water level at much greater distances. Yes, you cannot see a center console much further out, but the center console is much less a threat than a ship.

Distance eyeballs (or radar) can see something is dependent both on the height of the eyeball and the height of the thing being looked upon.

I expect you know this but it is worth mentioning for others.

My use case is moving up estuary's at night and being able to discriminate moored boats that are close together, and inner harbor at night finding small aluminum fishing boats not much larger than a dinghy.

[mvmojo]

Take a hard look at the Simrad/B&G 4G digital radar. We had it on MOJO and the resolution was incredible, especially within 2-4 nm.
It was mounted about 16' above the water. Here's a panoramic photo of the anchorage at Block Island looking aft. The screen shot below is the Simrad radar also look aft on a 1/4 mi scale.



fog from aft deck.jpg Views: 129 Size: 147.5 KB ID: 251278" style="margin: 2px" />

[BigAl.NZ]

Originally Posted by mvmojo

Take a hard look at the Simrad/B&G 4G digital radar. We had it on MOJO and the resolution was incredible, especially within 2-4 nm.
It was mounted about 16' above the water. Here's a panoramic photo of the anchorage at Block Island looking aft. The screen shot below is the Simrad radar also look aft on a 1/4 mi scale.



Attachment 251278

Attachment 251279

Yeah I have heard the Halo's are amazing. Unfortunatly we are a Raymarine ship for everything else.......a bit hard to justify changing the whole shop just for the radar.

Thats why I am looking at Raymarine Cyclone - its probably a bit better again than Halo - but it is that open array.

We cant user radar arch (though we have one) for moutning open array as thats where all our solar is.

It was only when I thought about where to mount an open array on a 40 foot yacht I realised I have never seen one on a yacht of that size.

[BigAl.NZ]

Originally Posted by wayne.b

===
An open array gives better target resolution regardless of height. Resolution is important for making sense of closely spaced targets or an irregular coast line.

An alternative to a pole is an aluminum tube radar arch which can also double as a dinghy davit.

Yeah we do actually have a SS radar arch already - but its filled with solar panels. Also that annoying back stay......

[hjohnson]

Originally Posted by BigAl.NZ

Does anyone have pictures of installation of an Open Array (3 foot) radar on a 40 footer?

I am looking at it as an option. Our dome was on front of mast, but this wont work for open array. I think on a pole on transom might be ok.

Draw back will be higher power, but the picture is far better.

I've seen open arrays mounted out front of the mast on larger sailboats. What they had, though, was a fiberglass cage just above it (to the swing diameter of the antenna) to keep lines from getting wrapped around it as it turns.


not sure how well it worked.